#! /bin/sh
### BEGIN INIT INFO
# Provides:          urandom
# Required-Start:    $remote_fs
# Required-Stop:     $remote_fs
# Default-Start:     S
# Default-Stop:      0 6
# Short-Description: Save and restore random seed between restarts.
# Description:       This script saves the random seed between restarts.
#                    It is called from the boot, halt and reboot scripts.
### END INIT INFO

[ -c /dev/urandom ] || exit 0

PATH=/sbin:/usr/sbin:/bin:/usr/bin
SAVEDFILE=/var/lib/urandom/random-seed
POOLSIZE=512
[ -f /proc/sys/kernel/random/poolsize ] && POOLSIZE="$(cat /proc/sys/kernel/random/poolsize)"
. /lib/init/vars.sh

. /lib/lsb/init-functions

do_status () {
	if [ -f $SAVEDFILE ] ; then
		return 0
	else
		return 4
	fi
}

case "$1" in
  start|"")
	[ "$VERBOSE" = no ] || log_action_begin_msg "Initializing random number generator"
	# Load and then save $POOLSIZE bytes,
	# which is the size of the entropy pool
	if [ -f "$SAVEDFILE" ]
	then
		# Handle locally increased pool size
		SAVEDSIZE="$(find "$SAVEDFILE" -printf "%s")"
		if [ "$SAVEDSIZE" -gt "$POOLSIZE" ]
		then
			[ -w /proc/sys/kernel/random/poolsize ] && echo $POOLSIZE > /proc/sys/kernel/random/poolsize
			POOLSIZE=$SAVEDSIZE
		fi
		cat "$SAVEDFILE" >/dev/urandom
	fi
	rm -f $SAVEDFILE
	# Hm, why is the saved pool re-created at boot? [pere 2009-09-03]
	umask 077
	dd if=/dev/urandom of=$SAVEDFILE bs=$POOLSIZE count=1 >/dev/null 2>&1
	ES=$?
	umask 022
	[ "$VERBOSE" = no ] || log_action_end_msg $ES
	;;
  stop)
	# Carry a random seed from shut-down to start-up;
	# see documentation in linux/drivers/char/random.c
	[ "$VERBOSE" = no ] || log_action_begin_msg "Saving random seed"
	umask 077
	dd if=/dev/urandom of=$SAVEDFILE bs=$POOLSIZE count=1 >/dev/null 2>&1
	ES=$?
	[ "$VERBOSE" = no ] || log_action_end_msg $ES
	;;
  status)
	do_status
	exit $?
	;;
  restart|reload|force-reload)
	echo "Error: argument '$1' not supported" >&2
	exit 3
	;;
  *)
	echo "Usage: urandom start|stop" >&2
	exit 3
	;;
esac

:
